Werner complexes of 4-ethyl pyridine



United States WERNER CONIPLEXES F 4-ETHYL PYREDINE William D. Schaefier, Berkeley, Calif., assignor to Union Oil Company of California, Los Angeles, Calif., a corporation of California N 0 Drawing. ApplicationNovernber 4, 1954. Serial No. 466,938

Claims. (Cl. 260-270) KAT wherein X is manganese, iron, cobalt or nickel, and. A is a monovalent anion.

The new complexes are useful as selective clathrateformers for separating mixtures of organic compounds which are chemically and physically similar, but which differ in molecular configuration. For example, when the solid complexes are triturated with, or formed in the presence of, a liquid mixture of isomeric xylenes it is found that one xylene isomer is selectively integrated into the crystal structure, forming what is presently regarded as a clathrate. The solid clathrate may then be separated from the liquid phase, and decomposed with acid or heat to recover the selectively clathrated hydrocarbon. The herein claimed complexes are of particular value for separating xylenes because the 4-ethylpyridine component boils at 166 C., and hence may be easily separated from the clathrated xylenes which boii at 1394-45 0. Gther nitrogen bases such as gamma picoline (B. P. 143 C.) are disadvantageous from this standpoint.

The new complexes may be easily prepared by simply admixing the proper mole-ratios of metal salt and 4- ethylpyridine, normally at room temperatures, although higher or lower temperatures may be employed. If desired the metal salt XA may be first dissolved in a solvent such as water, and the complex precipitated by addition of 4-ethylpyridine. The actual final mole-proportion of 4-ethylpyridine in the solid complex may vary somewhat, but those containing substantially four moles per mole of salt are preferred.

Suitable metal salts include the halides, nitritcs, nitrates, thiocyanates, isothiocyanates, cyanides, azides, cyanates, isocyanates, formates, acetates, and the like. Specific examples of such salts are:

aten

Patented Mar. 18, 19 58 ice Nickelous chloride Nickelous nitrite Nickelous thiocyanate Manganous chloride Manganous cyanide Cobaltous bromide Cobaltous acetate Ferrous thiocyanate Ferrous cyanate When working im aqueous solution, it is not essential to employ the actual salt desired in the final complex; the desired salt may be formed in situ by metathesis during the formation of the complex, as for example:

The Fe;(SCN) forms a less soluble complex with the added 4.-ethylpyridine than does the FeSO and hence the above equation is driven substantially to completion, with formation of the highly insoluble ferrous thiocyanate complex. Where the desired complex is more soluble in water, other solvents may be employed, or the complex may be prepared in the dry state, as by passing vapors of 4-ethylpyridine over the desired metal salt. Many other methods of preparation will be apparent to those skilled in the art.

Exampfes The invention is further illustrated, but is not limited, by the following technique which was utilized for preparing a series of the herein described complexes. The gen eral technique was as follows:

(1) A concentrated aqueous solution A was prepared containing one mole-proportion of the desired metal ion and two moleaproportions of the anion desired in the final complex. In some cases heating was employed to obtain complete solution.

(2) A second concentrated aqueous solution B was prepared, containing four mole-proportions of 4-ethyl Metal lon Anion Material employed nlekelouscobaltous.

manganous chloride. ferrous sulfate.

ba ous hlo ideformic acid.

sodium cyanide. manganous chloride. s um c ate.- sodlum thiocyanate.

The complexes so prepared and some of their properties are as follows:

Elemental analysis, Wt. Percent Melting Complex. Formula Color Izogt, Calculated Found 0 N V c 7 N 1. Nickel tetra-(-ethylpyridine) di- Pale blue 161 62.4 9.7 62.0 9. 7

Ni(Hcoo V N 4 (31 5 2. Manganous tetra-(-ethylpyridlne) Slightly pull-1.. 164, d. 60.6 10.1 60.4 7.2

dichloride. I Much 3. Manganous tetra-(-ethylpyrldiile} 7 Tan 300 67.3 15.7 48.9 17.1

dicyanide. MMCN.

4. Manganous tetra-(-ethylpyrldine) Tan 126 63.5 14.8 61.4 11.6

dlcyanate. NM ON 0 )T H v V 02H;-

' Cobalt tetra-(Hthylpyridine) d1 Pink I r N/ J4 r 6. Manganous tetra-(bethylpyridlne) Whi dlthlocyanate. M116 0 NM 7. Ferrous tetra-(kethylpyrldine) d1- Tan thiocyanate. I FKSGNM,

r 02 8. Nickel tetra-(4-ethyl pyridine) di- Bluel.

thlocyanate. N1(SCN)acompl 7 7 All of the above complexes are found to exhibit selective c'lathrating ability for one of the xylene isomers. Complexes l, 2, 3 and,4 selectively clathrate ortho-xylene in preference to the other isomers,-while complexes 5, 6, 7'

and 8 selectively clathrate the para-isomer.

In addition to their use as clathrate-formers, the complexes are also useful in other fields as e. g. insecticides; oil-soluble metal: carriers, oxidation accelerators for paints andthelike. 'Their' solubility' in most organic solvents, e. g. chloroform renders them useful as impreguants-for intimately depos'iting catalyticmetals on hydrophobic surfacesas e. g. activated carbon and the like. Otherjus'es willjjbe apparent to those skilled in the 7 1 "I application is'acontinuation-in-part of my prior applicationSerial No. 274,647, filed March. 3, 1952, and Seri l N 3 4 7115 p mb r 1 1 1 Other specific complexes, methods of preparation vand Low elemental carbon indicates this complex was not completely tetra-coordinated, but was partly the dlor trl-coordinate References Cited in the file of this patent Ploquin: Compte rendus, vol. 233, pp, 162-164 (1951).,

Logan: J. Am, Chem. Soc., vol. 74, pp. 5224-5 (1952). 

1. A TETRA-COORDINATED WERNER COMPLEX COMPOSED OF FOUR MOLE-PROPORTIONS OF 4-ETHYL PYRIDINE COORDINATED WITH ONE MOLE-PROPORTION OF A DITHIOCYANATE OF A METAL HAVING AN ATOMATIC NUMBER BETWEEN 25 AND 28 INCLUSIVE, SAID COMPLEX BEING CAPABLE OF FORMING A CLATHRATE WITH P-XYLENE IN PREFERENCE TO THE OTHER C-8 ALKARYL ISOMERS. 